Display an alert in Android while screen is locked

I am looking for a way to show the user a message开发者_JAVA技巧 on an Android device even when the screen is locked. What I've found is that most of the popup examples, such as SMS popups, appear only once - but won't display again the second time the user presses the power-button to turn the screen on (but leaves it locked).

I'd love any advice the community can provide on how to display a persistent message on the lock-screen.

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Tyr to use LayoutInflater and PopUpWindow class for this purpose